(1) Field of the Invention
The present invention relates to the fabrication of micro electro-mechanical devices, and more particularly, to a method of enlarging the tilt angle of a mirror structure for a double substrate spatial light modulator in the fabrication of micro electro-mechanical devices.
(2) Description of the Prior Art
A double substrate spatial light modulator includes mirrors suspended by hinges from an upper substrate. Individual mirrors can be selectively deflected to spatially modulate light incident to the upper substrate and then to reflect the light back to the upper substrate. This mirror can be defined as one pixel. It has been shown that an increased tilt angle of mirror motion improves the contrast ratio and gray scale of the mirror projector. Gray scale can be improved by providing multiple voltages so that the mirror can swing to more than two positions. These mirrors can be used in projector or high density TV (HDTV) applications, for example.
U.S. Pat. Nos. 6,356,378 and 6,046,840 to Huibers show a process for a double substrate reflective spatial light modulator. U.S. Pat. No. 6,337,760 B1 to Huibers et al shows an encapsulated multi-directional light beam steering device.